Oil-chamber for electric clocks



Patented Apr. 21, 1936 UNITED STATES.

PATENT OFFICE Walter Kohlhagen, Waterbury, Conn., assignor to The Waterbury Clock Company, Waterbury,

Conn., a corporation Application May 24, 1935, Serial No. 23,197

6 Claims.

This invention relates to an improvement in .oil-chambers, and particularly to oil-chambers for electric clocks and the like.

Oil-chambers for electric clocks, as general- 6 ly heretofore constructed, have been subject to relatively-rapid loss of the oil initially deposited therein. This loss has been occasioned largely by capillary action, which slowly but continually effects the withdrawal of the oil from within the oil-chamber to the outside thereof via the bearing-passage or passages through which one or more shafts extend.

One of the objects of the present invention is to provide an oil-chamber construction which,

while insuring adequate lubrication to such shafts as may project therefrom, will prevent or minimize the oil leakage due to capillary action.

A further object is to provide an oil-chamber in which the bearing-passage or passages thereof are assured of an adequate supply of oil without occasioning an objectionable outward pumping action which might ultimately drain the oil from the oil-chamber. I

Another object is toprovide a superior oilchamber construction in which the bearing-passage or passages leading therefrom and the rotary member or members mounted therein will coact to return only excess oil to the oil-chamber, and not deprive the coacting surfaces of the requisite amount of lubrication.

With the above and other objects in view, as will appear to those skilled in the art from the following, Vconsidered in conjunction with the accompanying drawing and appended claims, the

present invention includes all features disclosed therein which are novel over the prior art.

In the accompanying drawing:

Fig. 1 is a vertical central sectional View of a synchronous electric clock mechanism illustrating one form which the present invention may assume;

Fig. 2 is a sectional view taken on the line 2---2y of Fig. l;

Fig. 3 is a central longitudinal sectional view illustrating, on an enlarged scale, the right-hand bearing of the structure shown in Fig. 1; and

Fig. 4 is a central longitudinal sectional view illustrating another form which the present invention may assume.

The particular synchronous electric clock structure herein chosen for illustration includes a mounting-plate I0 having secured to its forward face, by means of screws II, a cup-shaped housing I2, which may be of any approved form 5 and may, for instance, be produced by die- (Ol. 30S-36.1)

casting. Interposed between the rear faceof the flange I3 of the housing I2 and the forward face of the mounting-plate Ill is a gasket I4, serving to prevent the leakage of a body of oil I5 contained within the vclosed chamber I6 with- -5 in the aforesaid housing I2.

Tightly mounted in a passage I1 in the mounting-plate I0 and projecting both forwardly and rearwardly therefrom is a sleeve I8 having a relatively-large longitudinal passageY I9 therein, i0 as shown particularly well in Fig. 1. The rear end of the passage I9 in the sleeve I8 is slightly enlarged to form a shoulder 20, against which is seated a rear bearing-bushing 2I held`rigidly in place by burring the metal of the "rear 15V end of the sleeve I8 thereover as at 22. The forward end of the sleeve I8-is similarly enlarged to provide an annular shoulder' 23v against which a front bearing-bushing 24 is held by means of a swaged-over portion 25 of the for- 2]'6 Ward end of the sleeve I8. y Mounted within and relatively-closely fitting the passage I9 in the'sleeve I8 is a capillary-tube |91* having an internally-threaded bore I Sb-of such direction as to tend to return oil inwardly 25 toward the bearing-bushing 24. Extending through the internally-threaded bore I9b of the capillary-tube I9a and through the bearing-passages 26 and 21 respectively formed in the bushings 2I and 24, is a shaft 28, preferably smaller in 80 diameter than the diameter of the threaded bore I9b of the capillary-tube |911. It has been found that satisfactory results are obtained when the threaded bore I9b, above referred to, is substantially .008 larger than the diameter of the said 35 shaft 28, to thus create a capillary space.

The shaft 28, just above referred to, mounts at its rear end a rotor 29 and may, for convenience of description, be designated as the power-input shaft. 'I'he rotor 29 forms avfeature of an elec- 40 tric motor which requires no detaileddescription other than to say that it includes a stator-structure 30 of iron or equivalent material and mounts a usual coil or solenoid 3l.

The motor including the parts 29, 30 and 3| in 45 the present structure is intended to function as a synchronous electric motor to impart accuratelytimed rotation to a shaft 32, which latter may be designated,'for convenience of description, as the power-output shaft, inasmuch as it may serve to 50 drive a hand or pointer 33 or other suitable timing element.

The forward end of the power-input shaft 28, before referred to, rigidly mounts a pinion 34 meshing into and driving a gear-wheel 35 rotat- 55 ing as a unit with a pinion 36. The last-mentioned pinion 36 meshes into and drives a gearwheel 31, rigidly attached to a pinion 38 which in turn meshes into and drives a gear-wheel 39, which latter, like the gear-wheels 35 and 31, before described, is rigidly secured to a complementary pinion, such as 40. The pinion 40 meshes into and drives a gear-wheel 4I, meshing into and driving a pinion 42, rigidly attached to the rear end of the power-output shaft 32, before referred to.

The hand or pointer 33 at the outer end of the shaft 32 may, for instance, constitute the seconds pointer of a synchronous electric clock, and for the purpose of taking off power to drive a minutepointer and an hour-pointer, the shaft 32 is provided about midway of its length with a pinion 43. The pinion 43, just referred to, when staked to the shaft 32, serves to restrain the inward axial movement of the latter in a bearing-passage 44 extending through the forward wall of the cupshaped housing I2, and through a rearwardlyextending boss 45 formed integral with the said wall.

From the foregoing, it will be seen that within the closed chamber I6 is provided a supply of lubricant I5 and a suitable gear-train enabling the power-input shaft 28 to effect the accuratelytimed rotation of the power-output shaft at a greatly-reduced speed.

The oil I5 within the closed chamber I 6 will be distributed by the various gears and pinions to the bearing-passages 26, 21 and 44, and if unrestrained such oil would slowly but continuously exude to the exterior of the structure through the bearing-passages 26 and 44, and ultimately drain the supply of oil from the said chamber I6.

To prevent the undue exuding of oil and at the same time insure the adequate lubrication of the bearings, the interior surface of the bearingbushing 2| is provided with a relatively-coarse pitch helical oil-return groove 46, which, it is to be noted, communicates with the longitudinal passage I9 in the sleeve I8. The outer end of the oil-return groove 46 intersects the rear face of the bearing-bushing 2I, but this feature is not essential inasmuch as the said groove may stop short of the rear face of the said bushing. The steepness of the pitch of the oil-return groove 46 results in the formation of a spiral land-like bearing-surface of adequate area upon the interior surface of the passage 26 in the bushing 2 I.

In the course of time, as oil from the chamber I 6 travels along the shaft 28 and tends to move outwardly through the minute space between the periphery of the said shaft and the surface of the bearing-passage 26 in the bushing 2 I, the major portion of the said oil will be forced back through the helical oil-return passage 46 into the interior of the passage I9. This effect is accomplished by inclining the groove 46 in such direction with respect to the direction of rotation of the shaft 28, that the surface of the said shaft will tend to wipe the oil inwardly along the said groove. The coaction of the surface of the shaft 28 and the groove 45, as above described, will return to the chamber I6 any excess oil, and thus prevent o-r minimize the outward leakage of lubricant Without, however, depriving the bearingpassage 26 of sufficient oil to effectively minimize wear.

In a manner similar to the treatment of the bearing-passage 26, the bearing-passage 44 in the housing I2 and its integral boss 45 may be provided with a steep-pitch helical oil-return groove 41, preferably communicating with the rear end of the said boss and hence with the interior of the chamber I6. In this instance, also, the direction of the helical oil-return groove 41 is such that the periphery of the power-output shaft 32, in cooperating therewith, will tend to force excess oil rearwardly back into the chamber I6.

As shown in Fig. 4, a shaft 48 may be provided at spaced-apart points with steeply-inclined oilreturn grooves 49 and 59 respectively cooperating with the interior bearing-surfaces of bearingbushings 5I and 52, to prevent the undue escape of oil from an oil-chamber or reservoir 53 within a tubular body-member 54.

From the foregoing, it will be seen that in a simple way, the effect of capillary action in causing oil leakage is effectively counteracted by the coaction of a bearing-surface with a properlyinclined groove in a complementary bearing-surface, thus effectively solving one of the most troublesome of the problems which have long confronted the makers of electric clocks. It is appreciated in this connection that the average users of clocks cannot be relied upon to replenish the oil-supply of an electric clock, with the result, in ordinary cases, that the bearings soon go dry and objectionable wear and noise result. By means of the present invention, the mechanism is `assured of an adequate supply of lubricant throughout a long period exceeding that which has heretofore been feasible.

The invention may be carried out in other specic ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be: embraced therein.

I claim:

1. An oil-chamber construction of the class referred to, including: a housing-structure providing a closed oil-chamber therein, and having a bearing-passage leading from its interior to its exterior; and a shaft rotatably bearing directly in the bearing-passage of the said housing-structure; one at least of the coacting-surfaces of the said bearing-passage and the said shaft being provided with a helical oil-return groove, the convolutions of which arey walled off from each other by flat-faced bearing-lands, which latter actually support the weight of the said shaft, the direction of relative rotation be- "f tween the said shaft and the surface of the said bearing-passage being such that the enacting-surfaces effect the wiping of excess oil inwardly through the said helical oil-return groove toward the oil-chamber in the said housing-structure.

2. An oil-chamber construction of the .class referred to, including: a housing-structure providing an oil-chamber therein, and having a bearing-passage leading from its interior to its exterior; and a shaft rotatably bearing directly in the bearing-passage of the said housing-structure; one at least of the coacting-surfaces of the said bearing-passage and the said shaft being provided with a helical cil-return groove leading to the interior of the oil-chamber within the said housing-structure, the convolutions ofthe said groove being walled off from each other by flat-faced bearing-lands, which latter actually support the weight of the said shaft, land the direction of relative rotation between the said shaft and the said bearing-passage being such that the coacting-surfaces effect the wiping of excess oil inwardly through the said helical groove into the oil-chamber in the said housing-structure.

3. An oil-chamber construction of the class reierred to, including: a housing-strucure providing a closed oil-chamber therein, and having a bearing-passage leading from its interior to its exterior, which bearing-passage is formed wlith a helical oil-return groove; and a shaft rotatably bearing directly in the bearing-passage of the said housing-structure; the convolutions of the said groove being walled off from each other by flat-faced bearing-lands, which latter actually support the weight of the said shaft; the direction of relative rotation between the said shaft and the said bearing-passage being such that the coacting-surfaces effect the wiping of excess oil inwardly through the said helical groove toward the oil-chamber in the said housing-structure.

4. An oil-chamber construction of theY class referred to, including: a housing-structure providing an oil-chamber therein, and having a bearing-passage leading from its interior to its exterior, which bearing-passage is formed with a helical oil-return groove connecting to the interior of the oil-chamber within the said housingstructure; and a shaft rotatably bearing directly in the bearing-passage of the said housing-structure; the convolutions of the said groove being walled ofi from each other by flat-faced bearinglands, which latter actually support the weight of the said shaft; the direction ci relative rotation between the said shaft and the said bearing-passage being such that the coacting-surfaces eiect the wiping of excess oil inwardly through the said helical groove into the oil-chamber in the said housing-structure.

5. An oil-chamber construction of the class referred to, including: a housing-structure providing a closed oil-chamber therein and having a bearing-passage leading from its interior to its exterior; and a shaft rotatably bearing directly in the bearing-passage of the said housing-structure and provided with a helical oil-return groove the convolutions of which are walled off from each other by `flat-faced bearing-lands, which latter actually support the weight of the said shaft; the direction of rotation of the said shaft with respect to the said bearing-passage being such that the coacting-surfaces effect the wiping of excess oil inwardly through the said helical groove toward the oil-chamber in the said housing-structure.

6. An. oil-chamber construction of the class re-4 ferred to, including: a housing-structure providing an oil-chamber therein and having a bearing-passage leading from its interior to its exterior; and a shaft rotatably bearing directly in the bearing-passage of the said housing-structure and provided with a helical oil-return groove connecting to the interior of the oilchamber within the said housing-structure the convolutions of which are walled off from each 

